That all would depend on how much much of a bf% increase you gain while bulking.
So that would also depend on what % you consider to be lean at.
If you want a guess you going to have to include what your bf% is when your at 160 or 150 so we have a referance to what you mean by lean nonlean ect...
From either of those numbers we can figure out the percent you lost from 160 to 150 and assuming your the same bf% at 180 after bulking as you were at 160 then we can find what the 150 would be equal to in relation to the after bulk.